1. Field of the Invention
The present invention relates to a technique of constructing a power tool having an electric motor.
2. Description of the Related Art
Japanese non-examined laid-open Utility Model Publication No. 57-111068 discloses an electric motor including an output shaft, a commutator and an armature fitted onto the output shaft and rotate together with the output shaft, brushes that supply current in sliding contact with the outer circumferential surface of the commutator, brush holders that house the respective brushes, a brush holder base that hold the brush holders, a cooling fan that rotates together with the output shaft and serves to cool the armature by means of cooling air, and a housing that houses these components. Further, according to the known electric motor, in order to ensure the smooth flow of the cooling air for cooling the armature via the cooling fan, a baffling member for guiding the cooling air is provided in a flow passage of the cooling air.
In a power tool having an electric motor of this type, it is desired to further improve the construction for guiding the cooling air particularly in order to reduce the size in the axial direction of the output shaft of the electric motor so that the power tool can be made compact.